WCF Web服务调用多个Web服务异步

Question

I am facing an issue from one WCF Web Service that I have created. This web service calls multiple web services to be able to build up its response for the caller.

var carInformation = Task.Run(() => carProvider.GetCarByCarNumberAsync(brandCode, carNumber));
var carHistory = Task.Run(() => carProvider.GetCarHistoryByCarNumberAsync(brandCode, carNumber));
var carConf = Task.Run(() => carProvider.GetConfByCarNumberAsync(brandCode, carNumber));
var carAdvSet = Task.Run(() => carProvider.GetAdvSetyByCarNumberAsync(brandCode, carNumber));
var carComp = Task.Run(() => carProvider.GetComponentsyByCarNumberAsync(brandCode, carNumber));
var carDealersComments = Task.Run(() => carProvider.GetDealerCommentsByCarNumberAsync(brandCode, carNumber));
var carPromotions = Task.Run(() => carProvider.GetCarPromotionsAsync(brandCode, carNumber));
var carCompetitors = Task.Run(() => carProvider.GetCompetitorsAsync(brandCode, carNumber));
var carSuppliers = Task.Run(() => carProvider.GetSupplierssAsync(brandCode, carNumber));

List<Task> taskList = new List<Task>();
taskList.Add(carInformation);
taskList.Add(carHistory);
taskList.Add(carAdvSet);
taskList.Add(carComp);
taskList.Add(carDealersComments);
taskList.Add(carPromotions);
taskList.Add(carCompetitors);
taskList.Add(carSuppliers);

await Task.WhenAll(taskList);

According to the above code snippet, I am expecting that all calls will get executed at the same time, since these are not dependent on each other. But this is not happening, when I look into the IIS Logs (from the other web service) or even if I user Fiddler to log all this requestes, I see only 5 are executed at the same time and the other ones are getting executed between the first are waiting for a response or in other cases are after one of those async calls had finalized.

Am I missing some configuration on the IIS that my web service is hosted? Or a setting in web config that allows more thread creation on PerCall.

Answer 1

WCF服务类上的[ServiceBehavior（UseSynchronizationContext = false）]属性将有所帮助。